Black disazo dye.



= i1 Miran STATES 7 PATENT Erica.

HEINRICH AUGUST BERNTI-ISEN, OF MANNHEIM, AND PAUL JULIUS, OF LUD- WIGSHAFEN, GERMANY, ASSIGNORS TO THE BADISOHE ANILIN AND SODA FABRIK, OF LUDWIGSHAFEN, GERMANY.

BLACK DISAZO DYE.

SPECIFICATION forming part of Letters Patent No. 644,240, dated February 2'7, 1900.

Application filed February 28, 1899. Serial No. 707,199. (Specimens) To aZZ whom it may concern.-

Be it known that we, HEINRICH AUGUST BERNTHSEN, doctor of philosophy, a subject of the King of Prussia, German Emperor, re-

5 siding at Mannheim, in the Grand Duchy of Baden, and PAUL JULIUS, doctorof philosophy, a subject of the Emperor of Austria- Hungary, residing at Ludwigshafen-on-the Rhine, in the Kingdom of Bavaria, Empire of Germany, have invented new and useful Improvements in the Manufacture of Disazo Coloring-Matters from Nitro-Amido-Phenol, (for which Letters Patent have been obtained in Germany, No. 323,247, dated August 19, 1898, and No. 323,984., dated December 27, 1898; in England, No. 26,262, dated December 12, 1898, and in France, No. 270,820, dated November 12, 1898,) of which the following is a specification.

We have invented new coloring-matters, which are the disazo coloringn1atters which can be derived from a nitro-amido-phenol. The nitro-amido-phenols which can be used in carrying out our invention are the orthoamido-para-nitro-phenol described byStuckenberg, (Aim-alen, Vol. 205, p. 72,) and paraamido ortho nitro phenol described by I'Iuebner, (Vol. 210, p. 382.) Both these nitroamido-phenols can be readily diazotized by treatment with hydrochloric acid and nitrite of soda. The diazo compounds obtained are with difficulty soluble and separate partly from the solution. As middle components we use alpha-naphthylamin and the Oleves sulfo-acids of alpha-naphthylamin-L6 or 1.7 or mixtures thereof, thereinafter termed Oleves acid. As end components which are particularly adapted for use in our invention we mention the following: beta-naphthol-3.6-disulfo-acid, (R-salt,) alpha-naphthol -4-sulfo-acid, alphanaphthol sulfoacid, alpha-naphthylamin, and 1.8-dioxynaphthalene--sulfo-acid.

In the present application forLetters Patent we wish to claim generically the new class of disazo coloring-matters defined, and

.specifically we desire to claim that member of the class which can be obtained from ortho amido para nitro phenol, using alphanaphthylamin as the middle component and 1.8-dioxy-naphthalenel-sulfo-acid as the end component.

The following example will serve to illus trate the manner in which our invention can be carried into practical effect. The parts are by weight:

EwampZeProdaetion of an intermediate coloring-matter from ortho-amido-para-iiitrophenol and alpha-naphthylamin.Dissolve about one hundred and fifty-four parts of ortho-amido-para-nitro-phenol in three hun= dred parts of hydrochloric acid (containing about thirty per cent. real HCl) diluted with five thousand parts of water and diazotize by adding a concentrated solution of sixty-nine parts of sodium nitrite. The diazo compound very soon separates out in the form of yellow-brown crystals. Pour the Whole into a solution of about one hundred and fifty parts of alpha-naphthylamin in one hundred and fifty parts of hydrochloric acid (containing about thirty per cent. real H01) and five thou sand parts of water. Stir the mixed solution while raising the temperature to from 35 to centigrade. Continue stirring at this temperature for about ten hours. The intermediate product, which possesses a metallic luster, separates out gradually but completely. Filter and Wash with Water.

Combination of the intermediate product with 1. 8-di0xy-naphthalenet-saUo-aeicl.Dissolve about three hundred and eight parts of intermediate coloring matter obtained as hereinbefore described in the first part of this example in about twenty thousand parts of water, to which one hundred and seventy parts of caustic-soda lye (containing about thirty-five per cent. real NaOH) have been added. 1001 the solution and add a concentrated aqueous solution of seventy-five parts of sodium nitrite and pour the whole mixture into two thousand five hundred parts of ice-water acidified with five hundred parts of hydrochloric acid, (containing about thirty per cent. real H01.) When the diazotation is entirely completed, run the mixture into an alkaline solution of about three hundred parts of the potassium salt of 1.8-dioxynaphthalenel-sulfo-acid. Precipitate the coloring-matter formed by means of common salt, collect by filtering, and press. It necessary, purify by redissolving and reprecipitating. The coloring-matter thus obtained is soluble in water, giving a blue-green solution and in concentrated sulfuric acid giving a blue-green solution. It dyes wool from the acid-bath, giving blue-black shades, and

these on treatment with chromates turn to a beautiful green-black.

The other members of our new class of coloring-matters can readily be obtained in a similar manner. Of course when combining a diazo compound with a base an excess of nitrous acid must be avoided, and the combination should be effected in acid solution.

Our coloring-matters are generally made in the form of a dark-colored powder and are characterized especially by their behavior on reduction. If a solution thereof be energetically reduced, a reduction product is obtained which may contain nitro-amido-phenol and perhaps di-amido-phenol, but this reduction product is not sufficiently conspicuously characterized to be readily recognized. Itis therefore advisable when testing for our coloring-matters to elit'ect a moderate reduction whereby the intermediate coloring-matter is regenerated, and this can be readily recognizedfor instance, by diazotizing and combining with R-salt. This test can, for instance, be carried out as follows: Dissolve from one-tenth to one-fifth gram of the coloring-matter in a little hot water, containing a large excess of ammonia. Boil the solution and add three to four drops of sulfid of ammonia. The solution is at first deep blue, next becomes discolored, and then assumes an intense-red to brown-red color. A spot of the solution on paper on treatment with hydrochloric acid changes color to violet or red-violet. Allow the reaction liquid to cool and precipitate gradually with hydrochloric acid. Collect the precipitate and filter. If

the product under examination be a member of our new class of coloring-matters, this precipitate is the corresponding intermediate product. It can be recognized by dissolving it in dilute caustic soda and adding sodium nitrite, While thoroughly cooling, and then adding hydrochloric acid. A diazo compound which is but slightly soluble separates out in a micro-crystalline form of brownish to black color. Run this diazo compound into a soda alkaline solution of R-salt, and immediately a deep-blue coloring-matter is obtained,which can be readily precipitated by common salt and more closely examined, if. desired.

Now What we claim is 1. The new disazo coloring-matters which can be obtained from nitro -amido-phenol which form'on partial reduction an intermediate product adapted for diazotation and combination with an alkaline solution of R- salt, substantially as described.

2. The specific disazo coloring-matter which can be obtained from ortho-amido-para-nitrophenol, alpha-naphthylamin, and LS-dioxynaphthalene-4-sulfo-acid, which yields upon partial reduction the intermediate product from ortho-atnido-para-nitro-phenol and alphanaphthylamin, and which is soluble in water and in concentrated sulfuric acid giving a blue-green solution, and dyes wool from the acid-bath giving blue-black shades, which turn to a beautiful green-black on treatment with chromates, all substantially as hereinbefore described.

In testimony whereof we have hereunto set our hands in the presence of two subscribing witnesses.

HEINRICH AUGUST BERNTIISEN. PAUL JULIUS.

Witnesses:

ERNEST F. EHRHARDT, HOWARD E. .T. INoLnY. 

